Dump contents of PostgreSQL database programmatically in python (w/out shell scripts)

How can one dump a PostgreSQL database programmatically, inside Python (or another language, if possible) without executing shell scripts.

Is this possible with psychopg2 or SQLAlchemy or some other library?

I want to dump all contents of the database, not just the schema. I do not want to dump the contents of just a query.

Currently I am using pg_dump -h localhost -U user -d db > db_dump.sql, however I would like to make use of a library to do this with python code.

The solutions I have already found typically resort to something along the lines of:

os.system(" pg_dump -h localhost -U user -d db > db_dump.sql ")

however this just asks the host machine to run the C implementation of pg_dump.

Similarly, I notice one can dump the contents of a query using something like:

cursor.execute(SELECT x FROM t)

f = open(db_dump.sql)

for row in cursor:

f.write("insert into t values (" + str(row) + ");")

However I want to save the contents of the entire database, not just a single query.

Can it be done with python directly?